Stacked Dielectric Filter Structure for Compact RF Coupling
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Solution Overview
Problem
Current TEM dielectric filters face challenges in miniaturization, power capacity, and low-end outband suppression performance due to their structural limitations, which hinder their ability to implement strong capacitive coupling and result in increased size and reliability risks.
Innovation Solution
A dielectric filter design involving stacked dielectric blocks with specific metal layer configurations and resonance through holes that facilitate capacitive coupling, reducing size while enhancing power capacity and suppressing low-end outband signals, achieved through the use of ceramic materials and optimized metal layer placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a stub type capacitive coupling structure is used in TEM dielectric filter, then the filter size is reduced, but the power capacity deteriorates and breakdown risk increases
Solution Approach 1:
The dielectric filter is divided into multiple dielectric blocks (first dielectric block, second dielectric block, etc.) that are stacked together. Each block contains specific through holes and blind holes with metal layers, creating segmented resonant structures that collectively achieve the desired filtering function while improving power capacity through distributed coupling structures.
Solution Approach 2:
The patent transitions from a single-plane stub coupling structure to a three-dimensional stacked configuration with through holes penetrating multiple dielectric blocks. This dimensional change enables capacitive coupling between adjacent blocks while maintaining compact size, and the vertical stacking provides additional space for optimized metal layer placement that improves power handling.
2Adaptability or versatility
If the depth of coupling blind hole is increased to implement weak capacitive coupling, then coupling strength is adjusted, but processing difficulty increases and reliability risk is caused due to small spacing
Solution Approach 1:
The coupling structure is segmented across multiple dielectric blocks, with each block containing portions of the coupling path. This segmentation allows independent optimization of each block's thickness and hole depth, making processing more manageable while achieving the desired coupling strength through the cumulative effect of multiple interfaces.
Solution Approach 2:
Metal layers are introduced as intermediary elements between dielectric blocks, forming capacitive coupling interfaces. These metal layers on the inner walls of through holes and blind holes provide controlled coupling strength without requiring extreme precision in hole depth, as the metal layer configuration can be adjusted to achieve the desired coupling effect.
3Power
If conventional coupling structures are used in TEM dielectric filter, then capacitive coupling is achieved, but low-end outband suppression performance deteriorates due to resonance frequency below operating frequency
Solution Approach 1:
The resonant structures are segmented into multiple dielectric blocks with distributed through holes and blind holes. This segmentation creates multiple resonant modes that can be engineered to suppress low-end outband frequencies while maintaining the desired operating band performance, avoiding the single resonant frequency problem of conventional structures.
Solution Approach 2:
The patent optimizes multiple parameters including the dimensions and positions of through holes, blind holes, and metal layers to control resonant frequencies. By adjusting these parameters, the filter achieves capacitive coupling capability while positioning resonant frequencies to provide effective low-end outband suppression rather than creating harmful resonances below the operating band.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables miniaturization of the dielectric filter with improved radio frequency performance, reduced electromagnetic leakage, and enhanced power capacity, while maintaining effective outband suppression without increasing the filter's size.
Implementation Method 1
the resonance through holes and the surrounding body form a resonance unit... electromagnetic waves in a quasi-TEM mode in the resonance through holes generate an induced current
Implementation Method 2
the metal layer on the first surface of the first dielectric block is opposite to the metal layer on the second surface of the second dielectric block... implementing capacitive coupling of electromagnetic energy
Data Source
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AI summary
Embodiments of this application disclose a dielectric filter and a communication device. The dielectric filter includes: a first dielectric block and a second dielectric block that are stacked up, where a first surface of the first dielectric block is opposite to a second surface of the second dielectric block; a first blind hole, a first through hole, and two or more resonance through holes whose openings are located on the first surface of the first dielectric block, and a second through hole whose opening is located on the second surface of the second dielectric block. A metal layer on the first surface of the first dielectric block is connected to a metal layer on the second surface of the second dielectric block. A metal layer on an inner wall of the first through hole is connected to the metal layer on the first surface of the first dielectric block. A metal layer on an inner wall of the first blind hole is connected to the metal layer on the first surface of the first dielectric block. A metal layer on an inner wall of the second through hole is connected to the metal layer on the second surface of the second dielectric block. This dielectric filter implements miniaturization and improves radio frequency performance of the dielectric filter.